An investigation into the mechanical and aesthetic properties of new generation coated nickel-titanium wires in the as-received state and after clinical use

Eur J Orthod. 2014 Jun;36(3):290-6. doi: 10.1093/ejo/cjt048. Epub 2013 Jul 19.

Abstract

Background/objectives: The purpose of this study was to compare the mechanical, structural, and aesthetic properties of two types of aesthetic coated nickel-titanium (NiTi) wires compared with comparable regular NiTi wires in the as-received state and after clinical use.

Materials/methods: Sixty one subjects were randomly assigned to four groups (N = 61), two groups of coated wires and two groups of comparable, non-coated controls (n = 15/group). The period in the mouth ranged from 4 to 12 weeks after insertion. In total, 121 wires (61 retrieved and 60 as-received) were used in the study. The percentages of coating retention and loss were extrapolated from scans. A brief survey of five questions with three choices was given to all patients. Differential scanning calorimetry (DSC) and three-point bending tests were done on as-received and used wires.

Results: The surface characterization by the percentage of resin remaining indicated that most wires in both test groups lost a significant amount of coating. A patient survey indicated that this was a noticeable feature for patients. DSC analysis of the wires indicated that the metallurgical properties of the coated wires were not similar to the uncoated wires in the as-received condition. Three-point bending results indicate a wide variation in test results with large standard deviations among all the groups.

Limitations: The extent of coating loss requires investigating, as do the biological properties of the detached coating.

Conclusions: Both wires lost a significant amount of aesthetic coating after varying periods in the mouth. The metallurgical testing of these findings may indicate that these wires perform differently in the mouth.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Calorimetry, Differential Scanning / methods
  • Child
  • Coated Materials, Biocompatible / chemistry
  • Dental Alloys / chemistry
  • Elasticity
  • Equipment Failure
  • Esthetics, Dental*
  • Female
  • Humans
  • Male
  • Materials Testing / methods
  • Nickel*
  • Orthodontic Appliance Design
  • Orthodontic Wires*
  • Pliability
  • Titanium*
  • Young Adult

Substances

  • Coated Materials, Biocompatible
  • Dental Alloys
  • titanium nickelide
  • Nickel
  • Titanium